In the production of magnet wheels for alternators with claws, it is known to use forging operations.
Rotors which are equipped with permanent interpolar magnets require the production of grooves for accommodation of the magnet, and magnet lips in the teeth of the magnet wheels. The magnet lips ensure retention in place of the permanent magnets which are subjected to the effects of centrifugal force when the rotor is rotating.
It is known to produce the grooves for accommodation of the magnet and the magnet lips by means of a machining operation which takes place after the forged magnet wheel has been obtained. In the industrial process for production of the magnet wheels, this machining operation has the disadvantage of increasing the duration of production and the cost of the part.
U.S. Pat. No. 7,676,902 B2 describes a method for production of a magnet wheel in which the operation of machining the grooves for accommodation of the magnet is eliminated. The magnet wheel is obtained by using only forging operations. The grooves for accommodation of the magnet and the magnet lips are pre-formed by hot forging. Cold forging tools are then used in order to complete the production of the grooves and lips, as well as the chamfers provided in the teeth of the magnet wheel. These cold forming tools are actuated radially, i.e. according to the radius of the magnet wheel.